Specific Heat Capacity of Solar Salt-Based Nanofluids: Molecular Dynamics Simulation and Experiment

Area of Science:

• Materials Science
• Nanotechnology
• Chemical Engineering

Background:

• Molten solar salts (MSS) are crucial for concentrated solar power (CSP) thermal energy storage.
• Enhancing the specific heat capacity (SHC) of MSS is vital for improving energy storage efficiency.
• Previous research suggests nanoparticle addition can increase MSS SHC, but theoretical validation is lacking.

Purpose of the Study:

• To experimentally determine the SHC of MSS with SiO2 nanoparticles.
• To theoretically investigate the mechanism behind SHC enhancement using molecular dynamics (MD) simulations.
• To verify experimental findings and explore the role of nanostructures in SHC increase.

Main Methods:

• Differential Scanning Calorimetry (DSC) was used to measure the SHC of MSS nanofluids with 1.0% SiO2 nanoparticles.
• Molecular Dynamics (MD) simulations were performed on pure MSS and mixtures with SiO2 nanoparticles and NaNO3 nanostructures.
• Simulations analyzed the impact of nanostructure formation, surface area, and surface energy on SHC.

Main Results:

• Experimental analysis showed a 15.65% average increase in SHC for MSS with 1.0% SiO2 nanoparticles.
• MD simulations revealed a maximum SHC increase of 25.03% with 13.71% NaNO3 nanostructures.
• Nanostructure formation, increased surface area, and surface energy positively influenced SHC, despite a slight decrease in base salt SHC.

Conclusions:

• The addition of SiO2 nanoparticles significantly enhances the SHC of molten solar salts.
• MD simulations provide a theoretical basis for the observed experimental enhancement, highlighting the role of nanostructures.
• Optimizing nanostructure content and properties in MSS nanofluids can lead to more efficient thermal energy storage systems.